Conventional residential washing machines typically utilize a mechanical agitator or pulsator within the clothes basket. This device takes up valuable space within the wash basket and, thus, reduces the volume of articles that can be loaded into the machine. In addition, significant energy is required to rotate or drive the agitator and the machine motor must be designed to handle the increased load of the agitator.
Attempts have been made to eliminate the agitator from residential washing machines. For example, U.S. Pat. No. 4,744,228 describes a system wherein a venturi extends through the bottom of the wash basket and is supplied with water from a pump. The venturi directs the water in a circular flow path within the wash basket, and drain opening in the tub direct the water back to the pump. The basket sits on rollers within the tub and a magnetic drive is used to spin the wash basket during the various wash cycles.
U.S. Pat. No. 7,637,129 describes a washing machine that uses high pressure angled air jets to create a circular swirl flow of water within a stationary tub to agitate and clean the clothes without rotating the tub.
A commercially available agitator-less washing machine is available from Whirlpool™ under the “Cabrio” name. Instead of an agitator, this machine utilizes a movable wash plate in the bottom of the basket to rock the clothes during the wash cycle. Kenmore™ offers a similar machine referred to as the “Oasis.”
Accordingly, the industry is continuously seeking improvements in washing machines that increase the load capacity by eliminating the central agitator while also reducing energy use and improving water management.